make mozhi not use 100 billion if statements + add TTS err handling

utils/main.go

@@ -1,6 +1,89 @@
 package utils
 
+import (
+	"errors"
+)
+
 type List struct {
 	Name string
 	Id   string
 }
+type LangOut struct {
+	Engine     string `json:"engine"`
+	AutoDetect string `json:"detected"`
+	OutputText string `json:"translated-text"`
+	SourceLang string `json:"source_language"`
+	TargetLang string `json:"target_language"`
+}
+
+func LangList(engine string, listType string) ([]List, error) {
+	var data []List
+	if listType != "sl" && listType != "tl" {
+		return []List{}, errors.New("list type invalid: either give tl for target languages or sl for source languages.")
+	}
+	if engine == "google" {
+		data = LangListGoogle("sl")
+	} else if engine == "libre" {
+		data = LangListLibreTranslate("sl")
+	} else if engine == "reverso" {
+		data = LangListReverso("sl")
+	} else if engine == "deepl" {
+		data = LangListDeepl("sl")
+	} else if engine == "watson" {
+		data = LangListWatson("sl")
+	} else if engine == "yandex" {
+		data = LangListYandex("sl")
+	} else if engine == "mymemory" {
+		data = LangListMyMemory("sl")
+	} else if engine == "duckduckgo" {
+		data = LangListDuckDuckGo("sl")
+	} else {
+		return []List{} , errors.New("Engine does not exist.")
+	}
+	return data, nil
+}
+
+// General function to translate stuff so there is no need for a huge if-block everywhere
+func Translate(engine string, to string, from string, text string) (LangOut, error) {
+	var err error
+	var data LangOut
+	if engine == "google" {
+		data, err = TranslateGoogle(to, from, text)
+	} else if engine == "libre" {
+		data, err = TranslateLibreTranslate(to, from, text)
+	} else if engine == "reverso" {
+		data, err = TranslateReverso(to, from, text)
+	} else if engine == "deepl" {
+		data, err = TranslateDeepl(to, from, text)
+	} else if engine == "watson" {
+		data, err = TranslateWatson(to, from, text)
+	} else if engine == "yandex" {
+		data, err = TranslateYandex(to, from, text)
+	} else if engine == "mymemory" {
+		data, err = TranslateMyMemory(to, from, text)
+	} else if engine == "duckduckgo" {
+		data, err = TranslateDuckDuckGo(to, from, text)
+	} else {
+		return LangOut{}, errors.New("Engine does not exist.")
+	}
+	if err != nil {
+		return LangOut{}, err
+	}
+	return data, nil
+}
+
+func TTS(engine string, lang string, text string) ([]byte, error) {
+	var err error
+	var data []byte
+	if engine == "google" {
+		data, err = TTSGoogle(lang, text)
+	} else if engine == "reverso" {
+		data, err = TTSReverso(lang, text)
+	} else {
+		return []byte(""), errors.New("Engine does not exist and/or doesn't support TTS.")
+	}
+	if err != nil {
+		return []byte(""), err
+	}
+	return data, nil
+}